need help with choosing right cables

Source first .the best speaker in the world cant make a bad source sound good.A good source can make an average speaker sound better.
Garbage in Garbage out.

Leafs, I used to believe that theory, particularly as to phono cartridges. But I now think that every link is equally important. However, I think that a poor speaker match is much harder to remedy than one involving the front end. Beyond a certain price point, I've found the performance differences among front end components much less profound than those among speakers at the same price point. And past a certain price point (which I would hope we are talking about here), most front end components are competent enough to not output garbage, but perhaps vary in reduced resolution or other miscues of omission. This is a much different situation from a $5000 speaker which leans warm or bright and requires a 400 wpc or a 10 wpc 300B amp to reach balance. The power amp in particular has a much more intimate sonic and electronic relationship with the speakers than it does with a DAC or phono stage. Witness the audiophile who forces his Transcendent 25 watt OTL upon his new Thiel 7.2s - a singularly unnatural marriage. Obviously, I do not advocate the purchase of junk front ends, and I never said as much. But speakers at every price point present a much wider spectrum of sonic and electronc variance, IMHO. Because of this, I've come to the conclusion that you start with the speaker, which fixes the range of usable associated electronics. By all means you should mate it to a quality, perhaps equally priced, front end from there

My advice was pretty bad. What you might do before you change any components, like another poster said, play with speaker positioning. Maybe try a pair of the acoustic imager foam rings to reduce diffraction if they fit on your speakers baffle, a $5 tweak. Depending on your room some profoam level one by RPG would smooth out some reflected energy for another $50 and, depending on the cabinets, if they resonate a bit, try some dynamat like material for another $20. I did the latter on a pair of klipsch epic series and while it never tamed my harshness, it did have the effect of adding a subwoofer, the bass tightened up and went deeper, it was neat. All three of those tweaks are far cheaper than any electronics upgrade and, IMHO, better than buying any cable. None of that will "break the bank" as you said. Maybe even get the monster out and try a little run of Kimber Kable 4PR, its cheap, or even try just straight 16g wire and stock interconnects and see how things sound. I'm not a fan of monster. And put the speaker grills on, that can help too. All those tweaks will run you around a hundred+ bucks.